1. Field of the Invention
This invention relates to a suede-like sheet material the substrate of which comprises a fibrous mat made of fibers that are bundles of finer fibers and two elastomers with which said fibrous mat is impregnated, said substrate having a nap on one side or on both sides thereof, and a method of producing the same.
2. Description of the Prior Art
A number of methods of producing a suede-like material having a nap resulting from finer-denier fibers have so far been proposed. For example, one method [method (a); cf. U.S. Pat. No. 3,706,613, British Pat. No. 1,241,382 German Pat. No. 1,901,209, French Pat. No. 2,000,223 and Canadian Pat. No. 910,140] comprises placing "oceano-insular" composite fibers in a fibrous mat such as a nonwoven fabric, said oceano-insular fibers each comprising a plurality of sectionally insular phases and a sectionally oceanic phase surrounding said insular phases, both of said insular and oceanic phases generally extending longitudinally along the fiber axis, and said oceano-insular fiber being produced by spinning of two or more polymers; temporarily fixing, or placing in a fixed state, said fibrous mat by treating the same with a sizing agent; removing said oceanic phase (so-called sea or matrix component); impregnating the mat with an elastomer; removing said sizing agent; and napping the surface of the resulting sheet material. Another method [method (b); cf. U.S. Pat. No. 3,424,604, British Pat. No. 1,094,064, German Pat. No. 1,469,550, French Pat. No. 1,420,623 and Canadian Pat. No. 789,966] comprises impregnating a fibrous mat prepared as in method (a) with an elastomer; removing the sea component; and napping the surface of the resulting sheet material. A further method [method (c); cf. Japanese Patent Application laid open under No. Sho-51-75178] comprises impregnating a fibrous mat prepared as in method (a) with an elastomer; removing the sea component; and reimpregnating the mat with an elastomer. However, the touch or feel of the sheet material produced by method (a) or (c) is far from those of a genuine suede of natural origin, because the elastomer invades the spaces formed after the removal of the sea component and produces a rubber-like touch or feel, that is a too high elasticity. On the other hand, the products made by method (b) are hardly balanced between surface characteristics, such as appearance of the nap and touch, and substrate characteristics, such as feel, drapability and sewability. Thus, if stress is laid on nap appearance, feel will be damaged and elasticity increased, while surface characteristics such as nap appearance will be inferior, if a serious view is taken of feel and sewability. These tendencies are also found in case method (a) or (c) is employed: thus, nap appearance is deteriorated, when the elastomer is varied so as to reduce the rubber-like touch and feel. Therefore, products with balanced surface and substrate characteristics can be produced only in a very narrow range of process conditions, and strict control of such conditions is required for a commercial production. As a result, production of a variety of suede-like sheet materials is quite difficult, and moreover production of suede-like sheet materials with satisfactory characteristics is also difficult.